For decades, tensions have been rising - Earth, Mars and the Belt are now on the brink of war.

All it will take is a single spark …

We begin, rather ominously, with a young woman, floating in tight metal quarters in zero gravity. We hear the sounds of some sort of commotion from outside her room, then silence.

She calls for help. She can't get out. She checks her water supply … two precious drops float in front of her face, as if mocking her. She guides them to her lips and swallows.

Finally, she manages to break free of the room, donning a space suit labeled with the name JULIE and the word SCOPULI. She puts on magnetic boots that allow her to move about in the gravity-less environment. As we will soon learn, this woman's name is Julie Mao.

She explores her seemingly deserted environment, noticing what looks like blood by the airlock door and an S.O.S. signal coming from the Engineering Bay. She stifles a shriek as a spacesuit floats past her … was there anybody inside it?

She makes her way to the Engineering Bay, which is enveloped in what looks like unstable blue lightning. A deformed figure cries out as it's sucked into this vortex, and the woman screams …

Now we're on Ceres, an asteroid that's been transformed into the most vital port in The Belt. As we learn from an angry street preacher, Ceres was once covered in ice … until Mars and Earth stole it all. The preacher rails against the slave-like conditions of the Belters who work the docks, living in a world where their air and water are rationed … and warns of an impending war between Mars and Earth, with Ceres caught in the middle.

Here we meet Joe Miller, a hard-boiled, hard-drinking, hat-wearing detective for Star Helix Security — and, according to the preacher, a welwala — a traitor to his people. He's showing the ropes to a new recruit, Dmitri Havelock, with their first stop being at a brothel. Via a series of Belter gestures and phrases, Miller comforts a prostitute, Gia, whose john — a Belter gangster — has just been killed by unidentified assailants. Havelock notices how Belters have long, thin limbs and fingers — the results of living without normal gravity, or in "low-G," as the saying goes.

Miller points out that Belters are very territorial and suspicious of those from Earth and Mars — "If you grew up with real sky over your head, and real gravity holding you on the ground, they're never going to trust you," he tells Havelock. Miller points out how you can spot those who are trying to hide the fact that they're Belters … until the bartender points out what gives away Miller himself: the spurs at the top of his spine where the bones didn't fuse right, the result of "cheap bone density juice" given to him when he was a ward of the state.

Back at Star Helix Headquarters, Captain Shaddid gives Miller his latest assignment: find Julie Mao, the daughter of Ariadne and Jules-Pierre Mao of Mao-Kwikowski Mercantile. A poor little rich heiress, Julie defied her parents by becoming a member of a student protest movement known as the Far Horizons Foundation … and the champion pilot of a racing ship known as the Razorback.

She's also the woman we met floating around in zero gravity in the very first scene.

As Miller does his homework on Mao, including asking his ex-lover and fellow cop, Octavia Muss, for her "woman's intuition" on the case, he has a change of heart about being on the take with Vargas, the owner of a sweatshop in which the children workers often develop "the Cough" due to the poor air filtration system. Miller throws Vargas into an airlock and lets him gasp for air himself for just long enough to make his point.

Meanwhile, on Earth, we meet Chrisjen Avasarala the U.N. Deputy Undersecretary, who's taken from an idyllic day with her husband Arjun Rao and grandson in her Westchester home to a U.N. black site, where U.N officials are interrogating Heikki Sobong, a member of the rabble-rousing Outer Planets Alliance (OPA) who's been accused of carrying contraband stealth technology. The OPA is a unsanctioned political group fighting for the Belt to become its own governing body.

Sobong is naked except for his shorts, chained to a wall, standing under his own weight. That's all that's needed to torture him, as Earth's gravity crushes his fragile Belter bones and lungs.

But Sobong's not talking. Avasarala tells her minions to leave him be for ten more hours and contact her if he survives.

Meanwhile, in outer space, the ice trawler Canterbury is about to deliver a shipment to Ceres Station when the crew receives a distress signal. As an investigation would mean a late arrival and therefore losing their on-time bonuses, Captain McDowell opts to purge the message as if they never received it … a decision that doesn't sit right with Second Officer James Holden, whom the Captain has been courting to be the ship's new XO upon the old one going crazy. Holden's usually content to have as little responsibility as possible as he romances the ship's navigator Ade Nygaard in zero gravity, but something about that transmission bothers him … especially when he enhances it to reveal a woman's voice saying "Please help me."

Unbeknownst to the crew except for the Canterbury's chief engineer, Naomi Nagata, Holden logs the message with HQ, which means the ship is now obliged to investigate. After performing a painful, high-G "flip and burn," the Canterbury approaches a wounded ship in the dead of space: the Scopuli.

Holden, Naomi, med-tech officer Shed Garvey, pilot Alex Kamal and mechanic Amos Burton take the Canterbury's shuttle, the Knight, to get a closer look and board the Scopuli (you'll recall, we saw Julie Mao at the beginning of the episode on a flightsuit that said "Scopuli"). They find no trace of any survivors (or our own Julie Mao) … and hightail it out of there once Captain McDowell informs them that an unidentified ship has entered their vicinity.

The mystery ship -- which Alex theorizes is Martian due to its advanced stealth tech -- fires torpedoes, which sail past the Knight and head straight for the Canterbury. Holden's lover, Ade, gives one last transmission: "There's something you should know …," before the Canterbury — and everyone on board — is blown to kingdom come.